In yarn feeding devices (with or without weft measuring device; with or without integrated brake ring; with rotatable winding element and stationary storage drum or with a rotatable storage drum as the winding element; for weaving machines or for knitting machines), there is a standardized construction used in the axial transition area from the housing to the winding element, as shown in EP 0 567 045 A1, FIG. 5 for a yarn feeding device with rotatable winding element and stationary storage drum. This means that an overlap with an open gap portion is provided between the annular edge of the winding element and the housing flange. The outer circumferential surface of the housing flange is smooth, as is the inner circumferential surface of the edge. Since the winding element rotates at a variable speed relative to the stationary housing flange, and since some clearance must be maintained between the ring and the housing flange because of manufacturing tolerances, the following phenomenon can be observed during operation of such a yarn feeding device: The processed yarn material constantly produces dirt, such as lint, dust, small fiber pieces, and the like, which tends to enter, inter alia, into the gap portion and to get stuck there and to travel gradually from the gap portion into the interior of the yarn feeding device, which may lead to operational malfunctions. Dirt gets, in particular, stuck to the inside of the ring, leading to the formation of a coherent dirt layer.
Attempts have already been made to integrate a fan into the yarn feeding device, wherein the fan comprises fan blades which rotate with the winding element, and produces a flow during operation in order to blow away dirt. As a result, however, dirt is increasingly sucked from the surroundings into the interior of the yarn feeding device.
It is known from U.S. Pat. No. 4,710,947 that the gap portion is designed in the manner of a labyrinth seal to make access more difficult for dirt. Nevertheless, deposits are formed that can grow inwards into the yarn feeding device.
It is the object of the present invention to improve a yarn feeding device of the above-mentioned type in a constructionally simple and inexpensive manner such that malfunctions caused by deposited dirt are largely avoided.